Over the years, power adapters have taken two forms—a power brick that requires a secondary AC cord, and a module (sometimes colloquially referred to as a “wallwart”) that plugs directly into the AC receptacle on the wall or power strip.
The wallwart is a lower cost solution because the cost of the AC power cord is eliminated. One issue with wallwarts, however, is that the form factor thereof varies with manufacturer and output power requirements. Wallwarts can become quite large and their size may render other AC sockets on the wall or power strip inaccessible to other devices.